Among so-called fuel cell vehicles equipped with fuel cells (e.g., polymer electrolyte fuel cells) as power generation apparatuses, some fuel cell vehicles are configured to, during low load operations such as idling, traveling at a low speed and regenerative braking, temporarily stop power generation of a fuel cell and supply electrical power from power storage units such as batteries and capacitors to power-consuming apparatuses (e.g., vehicle motors), in order to increase fuel efficiency (in this specification, such an operation mode is referred to as an “intermittent operation”).
During the intermittent operation, it is necessary to suppress an increase in an OCV (open circuit voltage) so that the fuel cell will not be degraded. In view of such circumstances, a technique has been known where a current sweep is performed to consume oxygen remaining in a cathode electrode, in order to maintain the electromotive force of the fuel cell so as to be equal to or lower than a degradation potential (for example, see patent document 1).
In addition, while the operation of the fuel cell is stopped, e.g., during the intermittent operation, whether or not a hydrogen leak or a cross leak occurs is judged based on a decrease in hydrogen pressure.
Patent document 1: JP2006-294304 A